1. Field of the Invention
The present invention relates to optical communication modules, and more particularly, relates to an optical communication module used for wavelength division multiplexing.
2. Description of the Related Art
In the field of optical communications, the transmission capacity per optical fiber cable has been increasing, and wavelength division multiplexing (WDM) as a communication method which realizes such increased transmission capacity is known. In wavelength division multiplexing, a plurality of optical signals with different wavelengths are simultaneously transmitted using a signal optical fiber.
An optical communication module used for wavelength division multiplexing is an optical transceiver. An optical transceiver used for wavelength division multiplexing includes at least a plurality of light sources that emit light beams (optical signals) with different wavelengths, a lens that condenses and collimates signals emitted from the light sources, and a multiplexing optical system that multiplexes optical signals condensed or collimated by the lens, and semiconductor lasers are used as the light sources in many cases.
In a known optical transceiver, a semiconductor laser serving as a light source, and a light condensing lens and a collimate lens (which will be hereinafter generally referred to as “lenses”) are mounted on a common supporting member.
When a semiconductor laser and a lens are mounted on the supporting member, position adjustment of the semiconductor laser and the lens is performed. Specifically, the relative positions of the semiconductor laser and the lens are fine-tuned such that the optical axis of an optical signal emitted from the semiconductor laser and the optical axis of the lens match one another. Conventionally, after the semiconductor laser is mounted on the mounting surface of the supporting member, the above-described alignment operation is performed by moving the lens in two axial directions or three axial directions (see Japanese Unexamined Patent Application Publication No. 2013-80900). In the following description, a direction which is parallel to the mounting surface of the supporting member and is orthogonal to the lens optical axis is defined as “the X-axis direction”. A direction which is parallel to the mounting surface of the supporting member and is also parallel to the lens optical axis is defined as “the Z-axis direction”. Furthermore, a direction which is perpendicular to the mounting surface of the supporting member and is orthogonal to the lens optical axis is defined as “the Y-axis direction”.